Sea Turtle Populations Spike With Warmer Temps, But Almost None are Male

Sea Turtles, who have been a long endangered species, are seeing tremendous spikes in birthrates this year along with warmer temperatures due to climate change.

However, the warmth is resulting in virtually all of them being born female.

“There are seven species of sea turtles, and all of them produce more females as it gets warmer,” said Lucy Hawkes, an ecologist from the University of Exeter who has been studying the phenomenon since 2007.

“All of them have strongly female biased sex ratios,” she said in an email to Insider.

Sea turtle eggs incubated in sand hotter than 88.8° Fahrenheit (31° Celsius) will be female, per the US National Oceanic and Atmospheric Administration.

The past four summers have been the hottest on record, Bette Zirkelbach, manager of the Turtle Hospital in Marathon, a city in the Florida Keys, told Reuters.

“Scientists that are studying sea turtle hatchlings and eggs have found no boy sea turtles, so only female sea turtles for the past four years,” she said.

The phenomenon has been observed around the world. A 2018 study found that 99% of turtles in Eastern Australia were female as well. 

Biologist David Owens, a professor emeritus at the College of Charleston told The Washington Post in 2018 that within a few decades to a century, “there will not be enough males in sea turtle populations.”

Having fewer males could lead to unsustainably poor genetic diversity among sea turtles, Melissa Rosales Rodriguez, a sea turtle keeper from the Miami Zoo, told Reuters.

Hawkes, however, told Insider it’s likely more complicated than that.

It’s unclear what the “optimal” gender balance should be, she said.

It’s common for a group of sea turtle nests to hatch about 90% females, and evidence suggests that only a few males are needed to fertilize all the eggs.

Scientists also say that of utmost importance is protecting the sanctuary beaches where they lay their eggs and to cease development of hotels and entertainment on those beaches.

Meanwhile beach crews have found the first sea turtle nest on the Mississippi mainland since 2018.

Watch the video below.

Cover photo by Kris-Mikael Krister on Unsplash.